//action.js
exports.requestPractice = function (practiceId) {
  return {
    type: ActionTypes.REQUEST_PRACTICE,
    practiceId
  };
};

exports.receivedPractice = function (practiceId, res) {
  return {
    type: ActionTypes.RECEIVE_PRACTICE,
    practiceId: practiceId,
    practice: res.data
  };
};

exports.fetchPractice = function (practiceId) {
  return function (dispatch) {
    dispatch(exports.requestPractice(practiceId));
    return fetch(`${Config.api}/practice?id=${practiceId}`, {
      credentials: 'same-origin'
    }).then(res => res.json())
      .then(json => dispatch(exports.receivedPractice(practiceId, json)));
  };
};

// 在container进行调用
componentDidMount:function(){
 // 直接进行请求
 fetchPractice(practiceId);
}

// 请求部分添加校验
exports.fetchPractice = function (practiceId) {
  return function (dispatch) {
    dispatch(exports.requestPractice(practiceId));
    return fetch(`${Config.api}/practice?id=${practiceId}`, {
      credentials: 'same-origin'
    }).then(Utils.checkStatus)
      .then(res => res.json())
      .then(Utils.checkCode)
      .then(json => dispatch(exports.receivedPractice(practiceId, json)));
  };
};

/**
 * 检查fetch请求返回是否报错
 * @param response
 */
exports.checkStatus = function (response) {
  let {status, statusText} = response;

  if (status >= 200 && status < 300) {
    return response;
  }

  let error = new Error();
  error = {
    status,
    msg: statusText
  };
  throw error;

};

/**
 * 检查code状态码
 * @param json
 */
exports.checkCode = function (json) {
  let {code, msg} = json;

  if (json.code === 0) {
    return json;
  }

  let error = new Error();
  error = {
    status: 200,
    code,
    msg
  };
  throw error;

};

// 调用action的时候捕获错误
// 将捕获到的错误通过error action设置到store的error字段中
// 从而引发错误提示component的渲染显示
fetchPractice(practiceId).catch(err => {
        fetchPracticeFail();
        setErrorTip(err);
      });